Interfolding of a web or sheet material (e.g., napkins, paper towels, tissue, etc.) is frequently performed using folding rolls of a folding machine. The folding rolls are operable to fold a series of successive sheets that are cut from one or more webs and supplied to the folding rolls in an overlapping relationship. Upstream of the folding rolls, the sheets are cut against a bed roll by a knife roll, and the sheets are then supplied to a retard roll that functions to provide the desired overlapping relationship of the sheets. From the retard roll, the sheets are advanced by a lap roll and are then supplied to the folding rolls for interfolding, to create a stack of interfolded sheets at the discharge of the folding rolls. A count roll is located adjacent the lap roll, and rotates in a timed relationship with the lap roll. The count roll is selectively operable to eliminate the sheet overlap at a desired sheet count, in order to create a separation in the supply of overlapped sheets to the folding rolls. The separation in the supply of sheets to the folding rolls functions to separate the stack of sheets discharged from the folding rolls into adjacent stacks or logs of sheets, each of which has a desired sheet count. The sheet overlap is interrupted by means of a vacuum system in the count roll that folds the leading edge of one of the sheets onto itself at the desired count. As the count roll rotates, the vacuum system is selectively actuated to engage the leading edge of the sheet as the sheets is transported on the lap roll, and carries and/or retains the leading edge of the sheet while the remainder of the sheet is advanced by the lap roll. The count roll then releases the leading edge of the sheet, and the retention of the remainder of the sheet on the count roll creates the sheet fold that eliminates the overlap between the leading edge of the sheet and the trailing edge of the downstream sheet.
However, known count roll systems for interfolding machines have drawbacks and limitations. For example, the operational speed of the interfolding machine is limited by a relatively short switching time that is available for actuating the vacuum system to turn the count roll valves on and off. Further, known count rolls use two vacuum ports on the count roll that are 180° apart, which can only provide an even count of sheets.